Bariatric surgery procedures, such as sleeve gastrectomy, the Roux-en-Y gastric bypass (RYGB) and the bileo-pancreatic diversion (BPD), modify food intake and/or absorption within the gastrointestinal system to effect weight loss in obese patients. These procedures affect metabolic processes within the gastrointestinal system, by either short circuiting certain natural pathways or creating different interactions between the consumed food, the digestive tract, its secretions and the neuro-hormonal system regulating food intake and metabolism. In the last few years there has been a growing clinical consensus that obese patients who undergo bariatric surgery see a remarkable resolution of their type-2 Diabetes Mellitus (T2DM) soon after the procedure. The remarkable resolution of diabetes after RYGB and BPD typically occurs too fast to be accounted for by weight loss alone, suggesting there may be a direct impact on glucose homeostasis. The mechanism of this resolution of T2DM is not well understood, and it is quite likely that multiple mechanisms are involved.
One of the drawbacks of bariatric surgical procedures is that they require fairly invasive surgery with potentially serious complications and long patient recovery periods. In recent years, there has been increased effort to develop minimally invasive procedures to mimic the effects of bariatric surgery. One such procedure involves the use of gastrointestinal implants that modify transport and absorption of food and organ secretions. For example, U.S. Pat. No. 7,476,256 describes an implant having a tubular sleeve with anchoring barbs, which offer the physician limited flexibility and are not readily removable or replaceable. Moreover, stents with active fixation means, such as barbs that deeply penetrate into surrounding tissue, may potentially cause tissue necrosis and erosion of the implants through the tissue, which can lead to complications, such as bacterial infection of the mucosal tissue or systemic infection. Also, due to the intermittent peristaltic motion within the digestive tract, implants such as stents have a tendency to migrate.
Gastroparesis is a chronic, symptomatic disorder of the stomach that is characterized by delayed gastric emptying in the absence of mechanical obstruction. The cause of gastroparesis is unknown, but it may be caused by a disruption of nerve signals to the intestine. The three most common etiologies are diabetes mellitus, idiopathic, and postsurgical. Other causes include medication, Parkinson's disease, collagen vascular disorders, thyroid dysfunction, liver disease, chronic renal insufficiency, and intestinal pseudo-obstruction. The prevalence of diabetic gastroparesis (DGP) appears to be higher in women than in men, for unknown reasons.
Diabetic gastroparesis affects about 40% of patients with type 1 diabetes and up to 30% of patients with type 2 diabetes and especially impacts those with long-standing disease. Both symptomatic and asymptomatic DGP seem to be associated with poor glycemic control by causing a mismatch between the action of insulin (or an oral hypoglycemic drug) and the absorption of nutrients. Treatment of gastroparesis depends on the severity of the symptoms.